Embedded electronic device and method for manufacturing an embedded electronic device

ABSTRACT

An embedded electronic device and a method for manufacturing the same wherein the embedded electronic device is composed of a printed circuit board, having a top surface and a bottom surface, a plurality of circuit components attached to the top surface of the printed circuit board having a plurality of standoffs on the bottom surface of the printed circuit board, a bottom overlay attached to the bottom surface of the printed circuit board, a top overlay positioned above the top surface of the printed circuit board and a core layer positioned between the top surface of the printed circuit board and the top overlay.

BACKGROUND OF THE INVENTION

The following description of the background of the invention is providedsimply as an aid in understanding the invention and is not admitted todescribe or constitute prior art to the invention.

Generally, embedded electronic devices can be used for variousapplications such as smart cards or tags. Smart cards/tags may be usedas credit cards, bankcards, ID cards, telephone cards, security cards orsimilar devices. Smart cards/tags are generally constructed byassembling several layers of plastic sheets in a sandwich array.Further, smart cards/tags contain embedded electronic components thatenable the smart card to perform a number of functions.

European Patent 0 350 179 discloses a smart card wherein electroniccircuitry is encapsulated in a layer of plastic material that isintroduced between the card's two surface layers. The method furthercomprises abutting a high tensile strength holding member against a sideof a mould, locating the smart card's electronic components with respectto that side and then injecting a reaction moldable polymeric materialinto the mould such that it encapsulates the electronic components.

European Patent Application 95400365.3 teaches a method for makingcontact-less smart cards. The method employs a rigid frame to positionand fix an electronic module in a void space between an upperthermoplastic sheet and a lower thermoplastic sheet. After the frame ismechanically affixed to the lower thermoplastic sheet, the void space isfilled with a polymerizable resin material.

U.S. Pat. No. 5,399,847 teaches a credit card that is comprised of threelayers, namely, a first outer layer, a second outer layer and anintermediate layer. The intermediate layer is formed by injection of athermoplastic binding material that encases the smart card's electronicelements (e.g., an IC chip and an antenna) in the intermediate layermaterial. The binding material is preferably made up of a blend ofcopolyamides or a glue having two or more chemically reactive componentsthat harden upon contact with air. The outer layers of this smart cardcan be made up of various polymeric materials such as polyvinyl chlorideor polyurethane.

U.S. Pat. No. 5,417,905 teaches a method for manufacturing plasticcredit cards wherein a mold tool comprised of two shells is closed todefine a cavity for producing such cards. A label or image support isplaced in each mold shell. The mold shells are then brought together anda thermoplastic material injected into the mold to form the card. Theinflowing plastic forces the labels or image supports against therespective mold faces.

U.S. Pat. No. 5,510,074 teaches a method of manufacturing smart cardshaving a card body with substantially parallel major sides, a supportmember with a graphic element on at least one side, and an electronicmodule comprising a contact array that is fixed to a chip. Themanufacturing method generally comprises the steps of: (1) placing thesupport member in a mold that defines the volume and shape of the card;(2) holding the support member against a first main wall of the mold;(3) injecting a thermoplastic material into the volume defined by thehollow space in order to fill that portion of the volume that is notoccupied by the support member; and (4) inserting an electronic moduleat an appropriate position in the thermoplastic material before theinjected material has the opportunity to completely solidify.

U.S. Pat. No. 4,339,407 discloses an electronic circuit encapsulationdevice in the form of a carrier having walls that have a specificarrangement of lands, grooves and bosses in combination with specificorifices. The mold's wall sections hold a circuit assembly in a givenalignment. The walls of the carrier are made of a slightly flexiblematerial in order to facilitate insertion of the smart card's electroniccircuitry. The carrier is capable of being inserted into an outer mold.This causes the carrier walls to move toward one another in order tohold the components securely in alignment during the injection of thethermoplastic material. The outside of the walls of the carrier hasprojections that serve to mate with detents on the walls of the mold inorder to locate and fix the carrier within the mold. The mold also hasholes to permit the escape of trapped gases.

U.S. Pat. No. 5,350,553 teaches a method of producing a decorativepattern on, and placing an electronic circuit in, a plastic card in aninjection molding machine. The method comprises the steps of: (a)introducing and positioning a film (e.g., a film bearing a decorativepattern), over an open mold cavity in the injection molding machine; (b)closing the mold cavity so that the film is fixed and clamped inposition therein; (c) inserting an electronic circuit chip through anaperture in the mold into the mold cavity in order to position the chipin the cavity; (d) injecting a thermoplastic support composition intothe mold cavity to form a unified card; and (e) thereafter, removing anyexcess material, opening the mold cavity and removing the card.

U.S. Pat. No. 4,961,893 teaches a smart card whose main feature is asupport element that supports an integrated circuit chip. The supportelement is used for positioning the chip inside a mold cavity. The cardbody is formed by injecting a plastic material into the cavity so thatthe chip is entirely embedded in the plastic material. In someembodiments, the edge regions of the support are clamped between theload bearing surfaces of the respective molds. The support element maybe a film that is peeled off the finished card or it may be a sheet thatremains as an integral part of the card. If the support element is apeel-off film, then any graphics elements contained therein aretransferred and remain visible on the card. If the support elementremains as an integral part of the card, then such graphics elements areformed on a face thereof and, hence, are visible to the card user.

U.S. Pat. No. 5,498,388 teaches a smart card device that includes a cardboard having a through opening. A semiconductor module is mounted ontothis opening. A resin is injected into the opening so that a resinmolding is formed under such condition that only an electrode terminalface for external connection of said semiconductor module is exposed.The card is completed by mounting a card board having a through openingonto a lower mold of two opposing molding dies, mounting a semiconductormodule onto the opening of said card board, tightening an upper die thathas a gate leading onto a lower die and injecting a resin into theopening via the gate.

U.S. Pat. No. 5,423,705 teaches a disc having a disc body made of athermoplastic injection molded material and a laminate layer that isintegrally joined to a disc body. The laminate layer includes an outerclear lamina and an inner white and opaque lamina. An imaging materialis sandwiched between these lamina.

U.S. Pat. No. 6,025,054 discloses a method for constructing a smart cardusing low shrinkage glue to hold the electronic devices in place duringthe devices immersion in thermosetting material that becomes the corelayer of the smart card. The method disclosed in U.S. Pat. No. 6,025,054has considerable drawbacks. Primarily, the disclosed method produceswarping and other undesirable physical defects caused by the curing ofthermosetting material. Further, this method is suitable only for cardshaving one or two components, thus limiting its functionality. Inaddition, the method disclosed in U.S. Pat. No. 6,025,054 createsdefects such as voids and air bubbles within a smart card because thegeometric shapes of the electronic components within the card obstructthe flow of the thermosetting material such that the thermosettingmaterial flows around the components faster than the air can be pushedout of the core of the smart card. Moreover, U.S. Pat. No. '054 requiresthe use of custom equipment, significantly limiting the scope andscalability of its application.

In view of the following, there is a need for a device and a method ofconstructing the device that is capable of housing numerous electricalcomponents.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, an embedded electronicdevice comprises a printed circuit board, having a top surface and abottom surface, wherein the bottom surface includes a plurality ofstandoffs, a plurality of circuit components attached to the top surfaceof the printed circuit board, a bottom overlay attached to the bottomsurface of the printed circuit board, a top overlay positioned above thetop surface of the printed circuit board and a core layer positionedbetween the top surface of the printed circuit board, the plurality ofcircuit components and the top overlay and further positioned betweenthe bottom surface of the double-sided printed circuit board and thebottom overlay.

According to another embodiment of the present invention, a method formanufacturing an embedded electronic device comprises providing aprinted circuit board having a top surface and a bottom surface, whereinthe bottom surface includes a plurality of standoffs, affixing aplurality of circuit components onto the top surface of the printedcircuit board, affixing the bottom surface of the printed circuit boardto a bottom overlay using a pressure sensitive adhesive tape or aspray-on adhesive, loading the printed circuit board and bottom overlayinto an injection molding apparatus, loading a top overlay positionedabove a top surface of the printed circuit board into the injectionmolding apparatus, injecting thermosetting polymeric material betweenthe top surface of the printed circuit board and the top overlay andinjecting thermosetting polymeric material between the bottom surface ofthe printed circuit board and the bottom overlay.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory only,and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will become apparent from the following description, appendedclaims, and the accompanying exemplary embodiments shown in thedrawings, which are briefly described below.

FIG. 1 is a sectional view of an embedded electronic device according toone embodiment of the present invention.

FIG. 2 is a top sectional view of an embedded electronic deviceaccording to one embodiment of the present invention.

FIG. 3 is a sectional view of an embedded electronic device and aninjection nozzle according to one embodiment of the present invention.

FIG. 4 is a sectional view of an embedded electronic device according toone embodiment of the present invention.

FIG. 5 is a top sectional view of a series of embedded electronicdevices formed on one molded sheet according to one embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings. It should be understood that thefollowing description is intended to describe exemplary embodiments ofthe invention, and not to limit the invention.

According to one embodiment of the present invention, as shown in FIG.1, an embedded electronic device 1 comprises a printed circuit board 10,a plurality of circuit components 20, a bottom overlay 30, a top overlay40 and a core layer 50. The embedded electronic device may be used insuch applications as smart cards, tags and/or wristbands.

The printed circuit board 10 has a top surface 11 and a bottom surface12. According to one embodiment of the invention, the printed circuitboard 10 is double-sided. Accordingly, the printed circuit board 10 isconfigured to accommodate a plurality of circuit traces 14 (shown inFIG. 2) on the top surface 11 and on the bottom surface 12. The circuittraces 14 are configured to operably connect the plurality of circuitcomponents 20 affixed to the printed circuit board 10. The circuittraces 14 electrically connect to the plurality of circuit components 20such that the circuit components are capable of performing electricalfunctions within the embedded electronic device 1.

The circuit traces 14 may be provided upon the surfaces 11, 12 of theprinted circuit board in numerous ways. For example, the circuit traces14 may be formed on the printed circuit board 10 with conductive ink. Inthe alternative, circuit traces 14 may be etched onto the printedcircuit board.

The printed circuit board 10 is comprised of any known conventionalmaterial suitable for receiving an electronic circuit. For example, theprinted circuit board 10 may be comprised of a flame retardant laminatewith a woven glass reinforced epoxy resin. This material is also knownas FR-4 board. Alternatively, the printed circuit board 10 may becomprised of a plastic compound that is suitable for receivingconductive ink.

According to one embodiment of the invention, as shown in FIGS. 1 and 3the bottom surface 12 of the printed circuit board 10 includes standoffs13. Preferably, the standoffs 13 are arranged in a dot-pattern on thebottom surface 12 of the printed circuit board 10 to allow the corelayer 50 to be positioned between the bottom surface 12 of the printedcircuit board 10 and the bottom overlay 30. The plurality of standoffs13 may be affixed to the bottom overlay 30 in a number of ways. Forexample, the plurality of standoffs 13 may be affixed using pressuresensitive adhesive tape or a spray-on adhesive. According to anotherembodiment of the invention, the plurality of standoffs 13 are comprisedof copper. According to yet another embodiment of the invention, circuitcomponents may be positioned on the bottom surface 12 of the printedcircuit board 10 along with a plurality of standoffs 13.

As shown in FIG. 1, and described below, the printed circuit board 10 isconfigured to receive and vertically stabilize a plurality of circuitcomponents. The plurality of circuit components 20 may be attached tothe printed circuit board 10 and specifically to the circuit traces 14by any one of a number of methods. For example, in one embodiment of theinvention, the circuit components 20 are connected to the printedcircuit board 10 with a conductive adhesive. Preferably, the pluralityof circuit components are soldered onto the printed circuit board 10.The plurality of circuit components 20 can be positioned anywhere on theprinted circuit board 10 as desired. The purpose of the embeddedelectronic device 1 and design parameters will dictate the position ofthe circuit traces 14 and the position of the circuit components 20.Functionality will also dictate what types of circuit components 20populate the printed circuit board 10.

For example purposes only, the plurality of circuit components 20 couldbe one of a battery, a button, a microprocessor chip or a speaker. Anyone or all of these circuit components could populate the printedcircuit board 10. Further, additional circuit components 20 may includebut are not limited to LEDs, flexible displays, RFID antennas andemulators. Referring to FIG. 2, a circuit layout for an embeddedelectronic device 1 is shown. The printed circuit board 10 shown in FIG.2 is populated by a battery 21, a microprocessor 22 and a button 23. Inanother embodiment of the present invention as shown in FIG. 2, theembedded electronic device 1 includes a liquid crystal display 24 as thecircuit component 20 connected to the button 23. The liquid crystaldisplay 24 may be used to display information to a user, such as anaccount balance. In the alternative or in addition to, the embeddedelectronic device 1 shown in FIG. 2 may include a speaker (not shown).

Generally, the components shown in FIG. 2 may vary in thickness andlength. For example purposes only, the battery 21 has a thickness of0.016 inches, the push button 23 has a thickness of 0.020 inches and themicroprocessor 22 has a thickness of 0.015 inches. In addition, theembedded electronic device 1 shown in FIG. 2 could have a speaker (notshown) having a thickness of 0.010 inches.

As shown in FIG. 1, a bottom overlay is attached to the bottom surface12 of the printed circuit board 10. The bottom overlay 30 can beattached to the printed circuit board 10 by any number of known methods.Preferably, the bottom surface 12 (having standoffs 13) is attached tothe bottom overlay 30 using a pressure sensitive adhesive tape or aspray-on adhesive. The bottom overlay 30 may be comprised of anysuitable material but preferably, the bottom overlay 30 is comprised ofpolyvinyl chloride (PVC) or like material. According to one embodimentof the invention, the surface of the bottom overlay 30 in contact withthe printed circuit board 10 has printed information. Alternativelyprinted information may be placed on the outside surface of the bottomoverlay 30. For example, the bottom overlay 30 may include printedinformation consistent with a standard credit card or identificationtag, including a name, expiration date and account number. According toanother embodiment of the invention, the bottom overlay 30 may be clearor ⅖ clear/white printed. Specifically, a 0.002 inch thick piece ofclear PVC material is laminated on to a layer of white PVC that is 0.005inches in thickness.

A top overlay 40 positioned above the top surface of the printed circuitboard 10 is shown in FIG. 1. The top overlay 40 may be comprised of anysuitable material, for example, the top overlay 40 may be comprised ofpolyvinyl chloride (PVC) or like material. According to one embodimentof the invention, the surface of the top overlay 40 in contact with thecore layer 50 has printed information. Alternatively, the outsidesurface of the top overlay 40 may have printed information. For example,the top overlay 40 may include printed information consistent with astandard credit card or identification tag, including a name, expirationdate and account number. According to another embodiment of theinvention, the top overlay 40 may be clear or “⅖ clear/white printed.”

As shown in FIG. 1, a core layer 50 is positioned between the topsurface of the printed circuit board 10 and the top overlay 40. Inaddition, as shown in FIG. 1, the core layer 50 is present in an areabelow the bottom surface 11 of the printed circuit board 10 and abovethe bottom overlay 30. Preferably, the core layer 50 is composed of athermosetting polymeric material. For example, the core layer 50 iscomposed of polyurea.

Polyurea is a known elastomer that is derived from the reaction productof an isocyanate component and a resin blend component. See What ispolyurea? THE POLYUREA DEVELOPMENT ASSOCIATION, athttp://www.pda-online.org/pda_resources/whatispoly.asp (last visitedMar. 21, 2006). The isocyanate can be aromatic or aliphatic in nature.Id. It can be monomer, polymer, or any variant reaction of isocyanates,quasi-prepolymer or a prepolymer. Id. The prepolymer, orquasi-prepolymer, can be made of an amine-terminated polymer resin, or ahydroxyl-terminated polymer resin. Id. The resin blend must be made upof amine-terminated polymer resins, and/or amine-terminated chainextenders. Id. The amine-terminated polymer resins will not have anyintentional hydroxyl moieties. Id. Any hydroxyls are the result ofincomplete conversion to the amine-terminated polymer resins. Id. Theresin blend may also contain additives, or non-primary components. Id.These additives may contain hydroxyls, such as pre-dispersed pigments ina polyol carrier. Id. Normally, the resin blend will not contain acatalyst(s). Id.

Polyurea has numerous advantages over other conventional materialscurrently being used in similar applications. Polyurea has a highresistance to UV light. In addition, polyurea has low elasticity andelongation characteristics. This enables the embedded electronic device1 to remain rigid. Further, polyurea has high bonding properties,allowing it to effectively bond the top and bottom overlays 40, 30 tothe circuit components. The circuit components are also held rigidly inplace due to the fact that polyurea has a low shrink factor. Theembedded electronic device of the present invention also possessdesirable environmental characteristics due to polyurea's low moistureabsorption and stability at high temperatures.

A method for manufacturing an electronic embedded device according tothe present invention will now be described.

First, a printed circuit board 10 is provided. The printed circuit board10 has a top surface 11 and a bottom surface 12. Circuit traces 14 arepresent on the top surface 11 of the printed circuit board 10.Alternatively, the printed circuit board may be double-sided havingcircuit traces 14 on the top surface 11 and the bottom surface 12.According to one embodiment of the invention, the bottom surface 12 ofthe printed circuit board 10 has a plurality of standoffs 14.

Next, a plurality of circuit components 20 are then positioned onto theprinted circuit board 10 and electrically connected to the circuittraces 14 on the top and or bottom surface of the printed circuit board10. The circuit components 20 may be connected by any one of severalmethods including the use of double-sided electrically conducting tape.Preferably, the plurality of circuit components 20 are connected via aconventional soldering process.

Next, the bottom surface 12 of the printed circuit board 10 is affixedto the bottom overlay 30. Preferably, the bottom surface 12 (havingstandoffs 13) is attached to the bottom overlay 30 using a pressuresensitive adhesive tape or a spray-on adhesive.

The printed circuit board 10, attached to the bottom overlay 30 is thenloaded as one complete sheet into an injection molding apparatus. A topoverlay 40 is placed into the injection molding apparatus and positionedsuch that the top overlay 40 is above the top surface 11 of the printedcircuit board 10. Specifically, the injection molding apparatus may be areaction injection molding machine (“which is often individuallyreferred to as “RIM”). These machines are associated with a top moldshell and a bottom mold shell that are capable of performing cold, lowpressure, forming operations on at least one of the sheets of polymericmaterial (e.g., PVC) that make up the top 40 and bottom 30 overlay. Suchtop and bottom mold shells cooperate in ways that are well known tothose skilled in the polymeric material molding arts.

The injection molding apparatus then injects thermosetting polymericmaterial via a nozzle 60 (shown in FIG. 3) between the top overlay 40and the bottom overlay 30 forming the core layer 50 from thermosettingpolymeric material. Preferably, as mentioned above, the thermosettingpolymeric material is polyurea.

Cold, low pressure forming conditions generally mean forming conditionswherein the temperature of the core layer 50 consisting of thermosettingpolymeric material, is less than the heat distortion temperature of thetop 40 and bottom 30 overlays, and the pressure is less than about 500psi. Preferably, the cold forming temperatures will be at least 100° F.less than the heat distortion temperature of the top 40 and bottom 30overlays. The heat distortion temperature of many polyvinyl chloride(PVC) materials is about 230 degrees F. Thus, the temperatures used tocold form such PVC sheets in the present invention will be no more thanabout (230° F.-100° F.) 130° F.

According to one embodiment of the invention, the more preferred cold,low pressure forming procedures will involve injection of thermosettingpolymeric materials with temperatures ranging from about 56° F. to about160° F., under pressures that preferably range from about atmosphericpressure to about 500 psi. In another embodiment of the invention, thetemperatures of the thermosetting polymeric material being injected intothe embedded electronic device 1 will be between about 100° F. and about120° F. under injection pressures that preferably range from about 80 to120 psi. In one embodiment of the invention, the liquid or semi-liquidthermosetting polymeric material will be injected under these preferredtemperature and pressure conditions at flow rates ranging from about 0.1to about 70 grams/second. Flow rates of 30 to 50 grams/second are evenmore preferred.

It should be noted that the use of such relatively cold, low pressure,forming conditions may require that any given gate (i.e., the passagewaythat connects a runner with each individual device-forming cavity) belarger than those gates used in prior art, hot, high pressureoperations. Preferably, the gates are relatively larger than prior artgates so that they are able to quickly pass the thermosetting polymericmaterial being injected under the cold, low pressure forming conditions.Similarly, the runner (i.e., the main thermosetting polymeric materialsupply passageway in the mold system that feeds from the source of thethermosetting material to each individual gate), will normally be in amulti-gate or manifold array, and, hence, should be capable ofsimultaneously supplying the number of gates/device-forming cavities(e.g., 4 to 8 cavities) in the manifold system at the relatively coldtemperature (e.g., 56° F. to 160° F.) and relatively low pressure (e.g.,atmospheric pressure to 500 psi) conditions used in the process. Theflow rates for the polymeric thermosetting material under the lowtemperature and pressure conditions are able to completely fill a givendevice-forming cavity in less than or about 10 seconds perdevice-forming cavity (and more preferably in less than about 3seconds). Preferably, device-forming cavity fill times of less than 1second are even more preferred. In view of these conditions, theprocesses may employ gates having a width that is a major fraction ofthe length of a leading edge of the device to be formed (that is, adevice edge that is connected to a gate). Preferably, the width of agiven gate is about 20 percent to about 200 percent of the width of theleading edge (or edges—multiple gates can be used to fill the samedevice-forming cavity), i.e., the “gated” edge(s), of the embeddedelectronic being formed.

Preferably, gates are employed that are tapered down from a relativelywide inflow area to a relatively narrow core region that ends at or nearthe leading edge(s) of the device being formed. Most preferably, thesegates will narrow down from a relatively wide diameter (e.g., from about5 to about 10 mm) injection port that is in fluid connection with thethermosetting material-supplying runner, to a relatively thin diameter(e.g., 0.10 mm) gate/device edge where the gate feeds the thermosettingmaterial into the void space which ultimately becomes the center or coreof the finished embedded electronic device 1. Gates that taper from aninitial diameter of about 7.0 millimeters down to a minimum diameter ofabout 0.13 mm will produce especially good results under the preferredcold, low-pressure injection conditions.

Another optional feature that can be used is the use of mold shells thathave one or more receptacles for receiving “excess” polymeric materialthat may be purposely injected into the void space between the top 40and bottom 30 layers in order to expunge any air and/or other gases(e.g., those gases formed by the exothermic chemical reactions thatoccur when the ingredients used to formulate most polymeric thermosetmaterials are mixed together) from said void space. These thermosetingredients are preferably mixed just prior to (e.g., fractions of asecond before) their injection into the void space.

After the injection of the thermosetting polymeric material, the moldedstructure is then removed from the injection molded apparatus. Accordingto one embodiment of the invention, several embedded electronic devices1 are cut out of one molded sheet. FIG. 5 depicts several embeddedelectronic devices formed on one sheet. According to another embodimentof the invention, the injected sheet corresponds to a embeddedelectronic device 1. The stiffness of the embedded electronic device 1will depend upon the materials used in the composition of each of theembedded electronic devices 1 individual components.

The finished embedded electronic devices 1 are then removed from theexcess polymeric materials (e.g., by trimming them off of the precursordevice body) and cut to certain prescribed sizes (e.g., 85.6 mm by 53.98mm as per ISO Standard 7810) dependent upon the functionality and designparameters of the embedded electronic device 1. The trimming process mayalso remove the excess material in one cutting/trimming operation. Italso will be well appreciated by those skilled in this art that themolding devices used to make such devices in commercial productionoperations will most preferably have mold shells having multiplecavities (e.g., 2, 4, 6, 8, etc.) for making several such devicessimultaneously.

The present invention has several advantages including a cost effectivemanner to produce one or more embedded electronic devices. Most of themodules in the embedded electronic device 1 can be constructed in atraditional manner that reduces manufacturing costs. In addition,through the use of polyurea and the standoffs, the method produces amore rigid card or tag that is less likely to have internal stresspoints that can cause deformation or warping. Moreover, the method ofthe present invention can be easily adapted to produce multiple embeddedelectronic devices at once.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and modifications and variations are possible in light of theabove teaching or may be acquired from practice of the invention. Theembodiment was chosen and described in order to explain the principlesof the invention and as a practical application to enable one skilled inthe art to utilize the invention in various embodiments and with variousmodification are suited to the particular use contemplated. It isintended that the scope of the invention be defined by the claimsappended hereto and their equivalents.

1. An embedded electronic device comprising: a printed circuit board,having a top surface and a bottom surface, wherein a plurality ofstandoffs are attached to the bottom surface; a plurality of circuitcomponents attached to the top surface of the printed circuit board; abottom overlay attached to the bottom surface of the printed circuitboard; a top overlay positioned above the top surface of the printedcircuit board; and a core layer positioned between the top surface ofthe printed circuit board and the top overlay and further positionedbetween the bottom surface of the printed circuit board and the bottomoverlay.
 2. The embedded electronic device of claim 1, wherein theprinted circuit board has a plurality of circuit traces on the topsurface configured to operably connect to the plurality of circuitcomponents and may have a plurality of circuit traces on the bottomsurface configured to operably connect to a plurality of circuitcomponents on the bottom surface of the printed circuit board.
 3. Theembedded electronic device of claim 2, wherein the plurality of circuittraces are formed with conductive ink.
 4. The embedded electronic deviceof claim 2, wherein the plurality of circuit traces are etched onto theprinted circuit board.
 5. The embedded electronic device of claim 1,wherein the plurality of standoffs are arranged in a dot-pattern on thebottom surface of the printed circuit board to allow the core layer tobe positioned between the bottom surface of the printed circuit boardand the bottom overlay.
 6. The embedded electronic device of claim 1,wherein the plurality of standoffs are affixed to the bottom overlaywith a pressure sensitive adhesive tape or a spray-on adhesive.
 7. Theembedded electronic device of claim 1, wherein the plurality ofstandoffs are copper.
 8. The embedded electronic device of claim 1,wherein the printed circuit board is composed of a flame retardantlaminate with woven glass reinforced epoxy resin (FR-4).
 9. The embeddedelectronic device of claim 1, wherein the top and bottom overlay areboth comprised of polyvinyl chloride.
 10. The embedded electronic deviceof claim 1, wherein the core layer is comprised of thermosettingpolyurea.
 11. The embedded electronic device of claim 1, wherein one ofthe plurality of circuit components includes at least one push button.12. The embedded electronic device of claim 1, wherein one of theplurality of circuit components includes at least one battery.
 13. Theembedded electronic device of claim 1, wherein one of the plurality ofcircuit components includes at least one microprocessor chip.
 14. Theembedded electronic device of claim 1, wherein one of the plurality ofcircuit components includes at least one speaker.
 15. A method formanufacturing an embedded electronic device, comprising: providing aprinted circuit board having a top surface and a bottom surface, whereina plurality of standoffs are attached to the bottom surface; affixing aplurality of circuit components onto the top surface of the printedcircuit board; affixing the bottom surface of the printed circuit boardto a bottom overlay using a pressure sensitive adhesive tape or aspray-on adhesive; loading the printed circuit board and bottom overlayinto an injection molding apparatus; loading a top overlay positionedabove a top surface of the printed circuit board into the injectionmolding apparatus; injecting thermosetting polymeric material betweenthe top surface of the printed circuit board, the plurality of circuitcomponents and the top overlay; and injecting thermosetting polymericmaterial between the bottom surface of the printed circuit board and thebottom overlay.
 16. The method of claim 15, wherein the thermosettingpolymeric material is polyurea.
 17. The method of claim 16, wherein theplurality of standoffs are arranged in a dot-pattern on the bottomsurface of the printed circuit board to allow the polyurea material tobe positioned between the bottom surface of the printed circuit boardand the bottom overlay.
 18. The method of claim 15, wherein a pluralityof embedded electronic devices are formed on one printed circuit board.19. The method of claim 15, further comprising: removing the injectedtop and bottom overlay from the mould; and cutting out the pluralityembedded electronic devices.
 20. The method of claim 15, wherein thecircuit traces are formed by etching traces into the printed circuitboard.